Unmanned Military Vehicles: Robots On The Rise

Unmanned vehicles represent the new cornerstone of the
military. The U.S. Army’s Future Combat Systems (FCS)
augmented its latest manned ground vehicles (MGVs) with
an array of unmanned air and ground vehicles. The U.S. Air
Force and Navy also have a number of unmanned vehicles in
the works and deployed around the world.

Because of their lower cost, these vehicles are quickly finding
their way into every military organization on the planet.
The U.S. Army expects 15 brigades to be equipped with complete
FCS vehicles by 2030.

The U.S. Air Force uses Northrop Grumman’s Global Hawk
surveillance aircraft to provide high-resolution synthetic aperture
radar (SAR) images with 1.0/0.3-m resolution (WAS/
Spot) (Fig. 1). It can survey as much as 40,000 square miles in
a day, with a maximum endurance of 35 hours. Powered by an
Allison Rolls-Royce AE3007H turbofan engine, it also has a
ceiling of 65,000 ft. The 32,250-lb unmanned aircraft features
a 130.9-ft wingspan and a payload of 3000 lb as well.

Some of the rugged subsystems within the Global Hawk
come from Curtiss-Wright Controls Embedded Computing,
including the Integrated Mission Management Computer
(IMMC) and Sensor Management Unit (SMU). An IPv6 Gigabit
Ethernet network provides the communication between
various modules.

As with most remote-control vehicles, the Global Hawk
utilizes wireless communication. Consequently, pilots can be
located on the other side of the planet. Removing the pilot from
the aircraft’s equation requires additional hardware, but it eliminates
an even greater amount of hardware needed to support a
human occupant.

The MQ-1 Predator (Fig. 2) and the MQ-9 Reaper
(Predator-B) are medium- to high-altitude, long-endurance
unmanned aerial vehicles (UAVs) that pack a punch. In addition
to surveillance chores, they can be armed with a range of
payloads including the GBU-12 Paveway II laser-guided bomb
and the AGM-114 Hellfire II air-to-ground missiles.

The 432d Air Wing from Creech Air Force Base (AFB),
located near Indian Springs, Nev., is the first wing that’s totally
dedicated to operating the MQ-1 Predator and MQ-9 Reaper.
The U.S. Air Force UAV Battlelab flight test and development
facility at Creech AFB is dedicated to developing UAVs. It’s
one of six original Air Force battlelabs operated under the Air
Warfare Center.

The Predator, smaller than the Global Hawk with its 66-ft
wingspan, can carry smart bombs in addition to heavy sensor
packages up to 1.5 tons on external hard points. Though not
as fleet as an F-16, the Predator’s endurance of 14+ hours
puts it in high demand on the battlefield.

As with the Global Hawk, Predator crew size isn’t limited
since it operates at a remote site. Shifts of pilots and operators
can handle a single vehicle, and work on unmanned vehicles
in general is moving toward a single pilot controlling multiple,
semi-autonomous vehicles at once.

This can also allow specialists to quickly move between
input sources by simply clicking on the appropriate window of
their command console. Having a team available means pilots and operators can be fresh even when the vehicle has been in the
air for half a day.

YOU’RE IN THE ARMY NOW
The air may be great for junior birdmen, but plenty of unmanned
vehicles roam down on the ground, too. There’s even a range of
small unmanned ground vehicles (SUGVs) like the Dragon Runner
from Foster-Miller (Fig. 3) or iRobot’s PackBot (see “Real-
World Robotics: An Appetite For Construction” at www.electronicdesign.com, ED Online 8076).

Standing only 5 in. tall, the Dragon Runner will give the Energizer
Bunny a run for its batteries. It’s designed to operate even after
being tossed through a window two or three flights up, over a wall, or
down a flight of stairs. This lets operators place the robot close to its
target before it proceeds under its own power. For great video of the
Dragon Runner in action, go to www.automatika.com/downloads/DR_Tough_Cookie.avi.

Foster-Miller’s 350-lb Modular Advanced Armed Robotic System
(MAARS) is the follow-up to the popular Talon and Talonbased
Special Weapons Observation Reconnaissance Detection
System (SWORDS). These platforms address a range of applications,
from explosive ordinance disposal (EOD) to offensive capabilities
like the Predator, albeit with bullets instead of missiles.

Land-based vehicles tend to have more challenges than airor
water-based vehicles because terrain and obstacles are major
issues. Aircraft often die when they hit obstacles. Underwater
vehicles operate in a similar open environment, but at slower
speeds. Likewise, surface water vehicles function in a relatively
open 2D environment.

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UNDERWATER CHALLENGES
The U.S. Navy is following a similar trend of large and small
remote-controlled underwater vehicles. For example, Boston
Engineering and the Franklin Olin College of Engineering are
teaming together under a U.S. Navy grant to create GhostSwimmer,
which will use Boston Engineering’s FlexStack. The Flex-
Stack computer is about the size of a coffee cup.

Unmanned underwater vehicles (UUVs) tend to be more challenging
because of power issues. Nonetheless, a variety of commercial
and military solutions is out there. Autonomous underwater
vehicles (AUVs) such as the Bluefin Robotics deep-water
Bluefin-21 BPAUV (Fig. 4) and Hydroid’s Remus 100 often
follow the design of torpedoes or submarines and utilize conventional
propellers for propulsion (see “Robobusiness 2007,” ED
Online 15723).

The Bluefin-21 BPAUV can operate for 18 hours at 3 knots.
Its 455-KHz sidescan sonar can cover widths up to 150 m with a
7.5- by 10-cm resolution. The BPAUV also can operate at depths
up to 200 m. Its self-contained navigational systems don’t require
acoustic beacons for positioning. The Bluefin-21’s battery modules
can be changed in under 2 hours, providing a fast turnaround
time. Possible uses include mine detection.

The Rafael Advanced Defense Systems Protector operates atop
the waves (Fig. 5). It can run autonomously or be remotely controlled.
It has been used for a range of missions, including anti-terror
force protection (AT/FP), intelligence, surveillance, and reconnaissance
(ISR), anti-surface warfare (ASuW), anti-submarine
warfare (ASW), and anti-mine warfare (AMW). It can be used for
long-range standoff surveillance or to patrol naval vessels.

The highly maneuverable, 30-ft Protector is based on a rigidhulled
inflatable boat. It has a low profile for a stealthy visual and
radar footprint. A diesel engine drives water jets, giving the Protector
a top speed of 40 knots. It can sport a range of devices, including
a Mini-Typhoon stabilized machine gun. On-mount cameras allow
day and night operation. Navigation can take advantage of GPS and
inertial navigation system (INS) support. The Protector can also utilize
radar, forward-looking infrared (FLIR), and laser range finders.

UNMANNED CHALLENGES
Lighter, cheaper, more compact designs are definite advantages to
unmanned vehicles, as is removing the human component from
harm’s way. Most unmanned vehicles carry heavy pricetags, but
these robotic vehicles are more disposable than their manned
counterparts, allowing for their use in more dangerous situations.

Not all is rosy when it comes to unmanned systems, though.
Issues of response time, field reliability, bandwidth, and even
congestion of frequencies used to control vehicles arise in the real
world. Response time is something any multiplayer gamer will
recognize. Lag, the delay between tapping a control and a visual
response, is often part of a game, but it can mean running a robot
off a cliff or stopping in time. Anticipation helps, but real-world
conditions can work against a reasonable response.

Bandwidth will be an issue with any wireless solution and even
some wired solutions. The Packbot from iRobot has an option to
deploy a fiber-optic cable behind itself, which provides plenty of
bandwidth, though wireless solutions have to contend with other
devices or robots. Various schemes can be employed to improve
bandwidth utilization, yet sorties may still need to be scheduled if
full utilization would exceed the communication limits.

And there are plenty of reasons to want more bandwidth. One
is vision fidelity. More cameras and sensors can improve situational
awareness for pilots and operators. They also allow more
information to be sent back instead of being stored in the vehicle.
In many instances, data must be stored in the vehicle because the
bandwidth required to transmit it is simply too great.

Bandwidth and reliability are two reasons why the U.S. Navy is
looking at multi-antenna multiple-input multiple-output (MIMO)
wireless technology from Silvus (Fig. 6). The technology is now
being tested at Space and Naval Warfare (SPAWAR) Systems Command,
as reliable communication is critical to remote operation.

Other challenges include power and cooling. Most unmanned
vehicles operate in rugged environments, requiring electronics
to be sealed. This tends to wreak havoc on electronics that like
to generate lots of heat, so low-power operation and low-power
devices are always desirable.

Cooling often remains an issue, even with low-power approaches.
Mercury Computer’s PowerBlock highlights the trend towards
compact, rugged platforms (Fig. 7). It’s literally a black box that
can house anything from a multicore PowerPC to a Cell processor
(see “CELL Processor Gets Ready To Entertain The Masses,” ED
Online 9748).

Used in the SAFE OPS test vehicle, Act/Technico’s RAIDstor
employs conduction cooling (Fig. 8). It provides network booting for
multiple single-board computers as well as data-recording storage.
Often, though, conduction cooling isn’t enough. This is where
alternatives such as liquid cooling come into play.

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SprayCool uses a two-phase liquid-cooling solution. The trick
is that SprayCool’s technology can work with air- or conductioncooled
boards with minimal modification. SprayCool’s enclosures
are sealed while providing high levels of cooling.

FPGAs can keep things cool by doing more in parallel while
running at slower speeds than today’s quad-core power consumers,
but they need to run in a rugged environment. Actel’s ProASIC3/
EL FPGAs meet this challenge, running at more than 250 MHz
at 125°C. The company’s Flash*Freeze mode lets them switch
from low-power mode to full operation in less than 1 µs. The
A3PE600L’s static power consumption is only 0.55 mW at 25°C.

AUTONOMOUS CHALLENGES
Remote-control vehicles dominate military applications because
of their reliability. Keeping a human in the loop can be important,
because making critical decisions with limited or contradictory
information is still best done by people.

This works well with remote-control vehicles as long as communication
can be maintained reliably. Unfortunately, reliable communications
isn’t always possible. It may not even be desirable in
some instances, since it could potentially give away the position of
the robot or its controller.

The current state of autonomous affairs is highlighted by competitions
like DARPA’s Grand Challenge and its recent Urban
Challenge, where teams built autos that faced demanding courses
without any drivers at all (see “Autonomous Vehicles Tackle The Urban
Jungle,” ED Online 13115).

Fully autonomous military vehicles with limited intelligence like
cruise missiles are used already. But applications such as ground
vehicles require greater intelligence due to the more complex
environment and conditions. A flying cruise missile always ends
in destruction, which isn’t a desirable characteristic for ground
vehicles designed to deliver supplies.

Still, a semi-autonomous mode is often attainable. In semiautonomous
mode, a robot vehicle will be given a simple command
such as fly a particular route and notify the pilot or operator if the
sensors detect something interesting. Likewise, having a vehicle
follow a person or another vehicle is a comparatively easy task.

Be they large or small, airborne or aquatic, unmanned vehicles will continue to improve and be deployed more heavily in the future. Significant improvements are in the works, but major design challenges
remain, especially as these robots move toward autonomous
operation.